http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=480ccac09aa5d010VgnVCM10000048f3d6a1RCRD
Filing Fee :
$595 plus a biometrics fee of $80; the fee total is $675. Applicants 75 years of age or older are not charged a biometric fee; their fee total is $595. No fee is required for military applicants filing under Section 328 and 329 of the INA.